Mr Khan said the attack gave extra weight to his case for improvements in funding for police in the capital.

“Today may not be the day to say this at the Cobra meeting, but I’m not going to resile from what I’ve been saying over the last 16 months, which is that London needs more resources to keep our city safe,” the Mayor told Sky News.

“Since 2010, we’ve lost hundreds of millions of pounds from the police budget, we’ve had to reduce police staff, we’ve had to sell off police stations.

“It’s simply not possible for a global city like London to carry on keeping our citizens, visitors and businesses safe if the Government carries on making the cuts they’ve been making.”

“The terrorists have stepped up attempts to kill us, to injure us, to disrupt our way of life. We’ve got to make sure we are alert and vigilant, but also that we are calm over the next few hours and days.

“Londoners will see an enhanced police presence and an increased police presence on our public transport network and across London.”

He said: “Thankfully, there aren’t any serious injuries, thankfully there aren’t any life-threatening injuries. But there are, I’m afraid, 18 people who’ve been taken to hospitals across London.

Forensic officers work at the Parsons Green Underground Station after an explosion in London (Pool via AP)

“I want to pay tribute to the police and security services who as we speak are following up various lines of inquiry to ensure that those responsible for this evil and cowardly attack are caught.

“If anybody has any information at all, it’s really important. You may think it’s trivial, you may think it doesn’t matter – let the police be the judges of that.

“A special counter terror hotline has been set up on 0800 789321. Please ring that hotline.

“We need to make sure that the public, who are the eyes and ears of the police and security services, provide police with the information they need.

“The focus today has to be apprehending and catching those responsible. I’m confident the police and security service are following up all the lines of inquiry they can.”